It is known from German utility model No. 75 37 867 to provide the longitudinal groove for guiding a push bar of a window or door frame, with ribs which extend at a distance from the rabbet surface and project from side walls of the longitudinal groove. In this prior art design, the push bar is mounted for displacement and rests in the upper groove portion against the front or top side of the ribs and is provided with holding means which engage the back or bottom side of the ribs from below, at uniformly spaced locations.
In order to adjust to definite wing sizes or to other fittings to be connected, it is necessary to cut the push bars to size. In such instances it may happen that the cut is made close behind a holding member, so that this member remains on the remnant cutoff and a great length of the push bar is no longer secured against lifting. Then, if a locking member is provided at the free end of the push bar, for example, a risk is run that under the relatively strong forces exerted to close the window and due to the unsatisfactory hold, the push bar will bend in the groove, and a secure locking is no longer ensured. If another push bar is provided instead of or in addition to the locking pin, a further risk is run that because of the bending, the two parts will disengage. Bridge-like covers might be provided as a remedy, however, these are additional parts which, in addition, must be mounted separately.